Structural modifications induced by electron irradiation in SiO2 glass: Local densification measurementsG. Buscarino, S. Agnello and F. M. Gelardi
Department of Physical and Astronomical Sciences, University of Palermo - Via Archirafi 36, I-90123 Palermo, Italy, EU
received 16 June 2009; accepted in final form 15 July 2009; published July 2009
published online 18 August 2009
We report a study on the structural modifications induced in amorphous silicon dioxide (a-SiO2) by electron irradiation in the dose range from 1.2103 to 5106 kGy. This study has been performed by investigating the properties of the 29Si hyperfine structure of the center by electron paramagnetic resonance (EPR) spectroscopy. Our data suggest that the structural modifications induced by irradiation take place through the nucleation of confined high-defective and densified regions statistically dispersed into the whole volume of the material. In addition, we have estimated that in the high dose limit (D 105 kGy) the degree of densification associated to the local (within the defective regions) polyamorphic transition follows a characteristic power law dependence on the dose given by , where b = (2.00.3)10-3, = 0.1600.004 and D is the irradiation dose measured in kGy.
61.80.Fe - Electron and positron radiation effects.
61.43.Fs - Glasses.
61.72.J- - Point defects and defect clusters.
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